WWII troop slang for military bureaucratic bullshit. The word implies that the regulations in question are so silly and trifling that they don't measure up to the level of bullshit. Subsequently, the word came to be merely an intensification of the epithet chicken.

In life and death matters, soldiers relied on their common sense and ignored the chickenshit regulations their superiors foisted upon them whenever possible.

According to Paul Fussel's book "Wartime," "Chickenshit refers to behavior that makes military life worse than it need be: petty harassment of the weak by the strong; open scrimmage for power and authority and prestige; sadism thinly disguised as necessary discipline; a constant 'paying off of old scores'; and insistence on the letter rather than the spirit of ordinances. Chickenshit is so called--instead of horse- or bull- or elephant shit--because it is small-minded and ignoble and takes the trivial seriously."

This definition is cited by at least two books by Steven E. Ambrose, "Citizen Soldiers" and "Band of Brothers."

Soldier 1: I got fined $25 this morning!

Soldier 2: What for?

Soldier 1: Some rear-echelon type saw me and said that I wasn't maintaing a professional appearance. I can't help it that we've been living in foxholes for the last week and because of the snipers, I can't shave.